Material breaking cartridge



Nov. 20, 1962 J. c. HESSON 3,0

MATERIAL BREAKING CARTRIDGE Filed Sept. 14, 1959 4 Sheets-Sheet l J m w w m 3 i ws w 5 .Q RR WW f u fi M @Y l we ma w 7 xg Flirt-la Nov. 20, 1962 J. c. HESSON MATERIAL BREAKING CARTRIDGE A n 0 m5 wn n. wk M9 w a 77? g m W m firm mm H mm 4 MW; w R Jim V $0 I am g R v. EM H mm Q ww R M WW w 5 M W m LE, Qml NW @N N J mmiwbwww R fa 3 mww Nov. 20, 1962 J. c. HESSON MATERIAL BREAKING CARTRIDGE 4 Sheets-Sheet 5 Filed Sept. 14, 1959 Aw .R ww m m M S R C Y Q% w M Q m QR ANN NAN MN NM. 9N \w% a 9% m Q @5 Q R \N .& hm kw NA \w ma EN me Q Q J. c. HESSON 3,064,574

MATERIAL BREAKING CARTRIDGE 4 Sheets-Sheet 4 ANN! Nov. 20, 1962 Filed Sept. 14, 1959 INVENTOR. James C? Wesson w s) QN QQ QQN 3,064,574 MATERIAL BREAKING CARTRmGE James C. Hesson, Riverdale, Ill., assignor, by mesne assignments, to Marrnon-Hern'ngton Company, Inc., Indianapolis, Ind., a corporation of Indiana Filed Sept. 1a, 1959, Ser. No. 839,878 8 Claims. (Cl. 102-25) This invention relates, generally, to material breaking cartridges and it has particular relation to such devices for use in coal mines for knocking down coal although its use is not so limited. It constitutes an improvement over the material breaking cartridge disclosed in application Serial No. 813,505, filed May '15, 1959, now abandoned, and assigned to the assignee of this application.

As pointed out in the application above referred'to, the construction of the material breaking cartridge is such that the discharge valve recloses when the pressure in the release chamber falls to a pressure which is substantially less than the pressure required for blasting and necessary to open the control valve. The reason for this is that the control valve automatically closes at this lower pressure. Then, due to the air under pressure that is trapped in the control chamber, the discharge valve recloses and holds the reduced pressure in the release chamber. Under certain circumstances it is desirable that the discharge valve remain open to substantially completely discharge the release chamber on reclosure of the control valve. For example, when the release chamber is fully discharged, there is no likelihood of the discharge valve opening inadvertently when the cartridge subsequently is handled in transferring it to another drilled hole in the coal face for another shot.

Accordingly, among the objects of this invention are: To provide for preventing reclosure of the discharge valve until the release chamber has been substantially completely discharged; to prevent such reclosure as long as compressed gas is supplied to the release chamber; to require that compressed gas no longer be supplied to the release chamber before the discharge valve is reset to closed position; to require that the blowdown valve in the air line supplying gas under pressure to the cartridge be closed before the discharge valve resets to the closed position; to increase the speed of opening movement of the discharge valve by venting the control chamber to the atmosphere through the lateral gas charge release ports shortly after they are unsealed by opening movement of the discharge valve; to close the end of the tubular discharge valve adjacent the release chamber and provide one or more discharge ports in this valve at the closed end through which the control chamber can be charged to hold this valve closed and through which the control chamber can be discharged to the atmosphere through the lateral gas charge release ports; to close the end of the tubular discharge valve by a removable cover or by a cover formed integrally with the valve body; and to reduce the length of the discharge head by telescoping one end of the discharge valve spring within the discharge valve.

Other objects of this invention will, in part, be obvious and in part appear hereinafter.

This invention is disclosed in the embodiments thereof shown in the accompanying drawings and it comprises the features of construction, combination of elements and arrangement of parts that will be exemplified in the constructions hereinafter set forth and the scope of the ap plication of which will be indicated in the appended claims.

For a more complete understanding of the nature and scope of this invention reference can be had to the following detailed description, taken together with the accompanying drawings, in which:

FIGURE 1 is a longitudinal sectional view of a material breaking cartridge in which the present invention is embodied, the cartridge being shown with the discharge valve and the control valve in the closed positions;

FIGURE 2 is a longitudinal sectional view, at an enlarged scale, of the discharge end of the material breaking cartridge shown in FIGURE 1 and again showing the discharge valve and the control valve in the closed positions;

FIGURE 3 is a view, similar to FIGURE 2, but showing the discharge valve and the control valve in the open positions in the initial discharging condition;

FIGURE 4 is a view, similar to FIGURE 3, but showing the discharge valve in the open position when the control valve is closed;

FIGURE 5 is an elevational view looking along the line 5-5 adjacent FIGURE 4 and showing the configuration of one of the lateral ports through which the gas charge escapes to perform the blasting operation;

FIGURE 6 is a view, similar to FIGURE 2, and showing a modified construction for the discharge valve which permits the use of a shorter discharge head, the discharge valve and control valve being shown in the closed positions;

FIGURE 7 is a view, similar to FIGURE 6, but showing the discharge valve in the open position;

FIGURE 8 is a vertical sectional view showing another form of discharge valve that can be employed in practicing this invention;

FIGURE 9 is a view, in end elevation, of the discharge valve shown in FIGURE 8;

FIGURE 10 is a vertical sectional view of another discharge valve that can be employed;

FIGURE 11 is a vertical sectional view of still another form of discharge valve that can be employed; and

FIGURE 12 is a view, in end elevation, of the discharge valve shown in FIGURE 11.

Referring now particularly to FIGURES l, 2, 3 and 4 of the drawings, it will be observed that the reference character 10 designates, generally, a material breaking cartridge in which the present invention is embodied. It includes a cartridge tube 11, preferably formed of high strength steel, and having a length depending upon the desired capacity of the cartridge 10. At the left end of the cartridge tube 11 there is a tube top 12. The tube top 12 is threaded into the left end of the cartridge tube 11 and an 0 ring 13 is provided therebetween for sealing purposes. At the left end of the tubetop 12 there is a tube top nose 14. Extending through the tube top nose 14 and protected thereby is an air supply tube '15 which is connected by a fitting 16 to the left end of the tube top 12. It will be understood that the air supply tube 15 is connected through a blowdown valve to a suitable source of high pressure air which can be supplied by a suitable high pressure compressor. The blowdown valve is arranged not only to control the flow of compressed gas to the cartridge tube 11 but also it can be arranged to discharge the cartridge tube 11 to the atmosphere, if desired.

At the right end of the cartridge tube 11 there is provided an extension adapter 17. It is threaded into an interior thread at this end of the cartridge tube 11. A discharge head body, tubular in shape, is indicated at 18 and it is threaded onto the extension adapter 17. The tubular head body 18 is provided with lateral ports 19 through which the compressed gas is discharged for material breaking purposes. Slidably mounted within the discharge head body 18 is a cup shaped discharge valve 20. The discharge valve 20 slides in a cylindrical control chamber 21 which is located within the discharge head body 18. The control chamber 21 is positioned end- -wise of a release chamber 22 which is formed in the cartridge tube 11 and extension adapter 17 where the gas charge is held in compressed state prior to being released 3 through the lateral ports 19 on movement of the discharge valve 20 to the open position.

As pointed out, the cup shaped discharge valve 20 closes off the lateral ports 19 until the gas pressure is to be released for blasting purposes. The discharge valve 20 at its left end is provided with a convex annular surface 23 that is arranged to have sealing engagement with an annular knife edge 24 which is formed on a replaceable valve seat 25 of hardened steel which is held in place on the right end of the extension adapter 17 by the tubular discharge head body 18 when it is threaded in place as shown in the drawings. An ring 26 is interposed between the replaceable valve seat 25 and the extension adapter 17 for sealing purposes.

For a purpose that will be apparent hereinafter the annular valve seat 25 has a counterbore 27 adjacent the annular knife edge 24 the surface of which merges with an inwardly flared annular surface 28 which connects it with the inner cylindrical surface 29 of the replaceable valve seat 25. Thus there is an inwardly flared surface from the annular knife edge 24.

The usual seals can be provided for the extension adapter 17 and for the discharge valve 20. As shown, an 0 ring 30 is interposed between the extension adapter 17 and the cartridge tube 11. An 0 ring 31 is located in a suitable peripheral groove in the discharge valve 20 and it provides sealing engagement between it and the inner cylindrical surface of the control chamber 21. These 0 rings and the other '0 rings referred to herein are of sufficient size as to completely fill the respective groove and to extend beyond the adjacent peripheral sur- 7 face in order to provide the required sealing action.

The discharge valve 20 is biased toward the left into closed position by a coil compression spring 32. It will be observed that the spring 3 2 at the left end. bears against an annular shoulder 33 on the discharge valve 20. At the other end the spring 32 bears against an annular shoulder 34 which forms a part of a valve seat member 35. On 0 ring 36 provides the sealing engagement between the valve seat member 35 and the discharge head body 18. The valve seat member 35 has an annular flange 37 which is held by a shoulder 38 on a control valve body 3-9 in the position at the right end of the discharge head body 18.

The right end of the control valve body 39 is closed by a cap that is indicated, generally, at 40. The cap 40 includes an internally threaded portion 41 with centrally located threads 42 for receiving an adjusting screw 43-. A cap screw 44 closes the outer end of the cap 40, as shown.

The adjusting screw 43 bears against a shim 47 and the arrangement is such as to vary the tension of a coil compression spring 48 that is located within the cap 40 for reaction against a control valve 49 which is slidable in a cylindrical valve chamber 50 that is formed in the control valve body '39. The control valve 49 is arranged to close oif vents or ports 51 otherwise placing the valve chamber 50 in communication with the atmosphere. Auxiliary vents or ports 52 are provided to maintain atmospheric air pressure on the right side of the control valve 49'.

Formed integrally with the control valve 49 is a hemispherical protuberance 53 which is arranged to have line contact engagement with a knife edge 54 that is formed around an opening through a hardened annular insert 55 which is positioned in a counterbore 56 formed in the flange 37. The hardened insert 55 is held in place by screws 57 and an 0 ring 58 provides sealing engagement between it and the main portion of the valve seat member 35.

Extending through the valve seat member 35 is a single discharge opening 61 a minor portion 62 of which has the same diameter as the diameter of the opening through the hardened insert 55. A major portion 63 of the discharge opening 61 flares to the left from the minor portion 62 into the control chamber 21.

4 As pointed out hereinbefore, it is desirable that the control chamber 21 be vented to the atmosphere through 1 the lateral ports 19 shortly after the discharge valve 20 moves toward the open position. One reason for this is to increase the speed of opening of the discharge valve 20. Another reason for this is to prevent the reclosure of V the discharge valve 20 as long as compressed gas conscopes within the walls of the discharge valve 20 and a shoulder 66 thereon limits the movement into the discharge valve 20. Radial ports 67 extend through the annular flange 65 underneath the cover 64 and between it and the convex annular surface 23 which has sealing engagement against the annular knife edge 24 which is carried by the replaceable valve seat 25.

The periphery 68 of the cover 64 is coextensive with the inner cylindrical surface 29 of the replaceable valve seat 25. The diameter of the cover 64 is less than the diameter of the cylindrical surface 29 by an amount sufficient to provide a clearance opening 69 of annular configuration between the periphery 68 of the cover 64 and the inner cylindrical surface 29' of the replaceable valve seat 25. This clearance is of the order of .00-3 to .006 inch.

As pointed out hereinafter, the cover 64 can be formed integrally with the discharge valve 20. Where it is formed as a separate element, it can be held in place by a bolt 76 which extends through it and through a bottom wall 71 of the discharge valve 26. Air equalizing openings 72 are located in the bottom wall 71 to permit the flow of compressed gas from the release chamber 22 through the radial ports 67 into the control chamber 21. In order to make certain that the portion of the control chamber 2'1 in which the spring 32 is located is vented, flutes 73 are provided at the left end of the valve seat member 35 against which the right end of the discharge valve 20 engages in the open position as shown in FIGURE 3 of the drawings.

In operation it will be assumed that the discharge valve 20 and the control valve 49 are in the closed positions shown in FIGURES 1 and 2 of the drawings. As compressed gas in the form of high pressure air flows into the cartridge tube 11 from the air supply tube 15, some of it flows past the cover 64 through the annular clearance opening 69 and through the radial ports 67 into the interior of the tubular discharge valve 20. Then it continues to flow through the air equalizing openings 72 into the control chamber 21. During the filling operation the pressure in the control chamber 21 is substantially equal to the pressure in the release chamber 22 and the discharge valve 20 is held closed because the area at the O ring 31 exposed to the pressure in the control chamber 21 is greater than the area of the discharge valve 20 at the knife edge 24 which is exposed to the same pressure in the release chamber 22. The pressure continues to build up in the release chamber 22 and in the control chamber 21 until it is suflicient to move the control valve 49 against the closing force of the spring 48 whereupon the control valve 49 opens, as shown in FIGURE 3 of the drawings, and the pressure in the control chamber 21 begins to be reduced for the reason that the compressed air in the control chamber 21 is vented through the cylindrical valve chamber 50 and the vents 51 to the atmosphere faster than it flows through the radial ports 67. When the force due to the gas pressure in the control chamber 21 times the area of the discharge valve 20 affected thereby plus the force exerted by the spring 32 becomes less than the force due to the pressure in the release chamber 22 times the area of the cover 64, the discharge valve 20 starts to open. As soon as the discharge valve 20' has opened slightly with the cover 64 still restricting the flow of air through the annular clearance opening 69, air can vent from the control chamber 21 through the air equalizing openings 72, the interior of the discharge valve 20 and through the radial ports 67 to the lateral discharge ports 19. This quickly vents the control chamber 21 to a low pressure so that the discharge valve 20 opens to the full extent, shown in FIGURE 3, suddenly even though the control valve 49 may partly close due to reduced pressure in the control chamber 21. Even when the control valve 49 recloses, as shown in FIGURE 4, the discharge valve 20 remains open until the pressure in the release chamber 22 has been substantially completely discharged. In the position of the discharge valve 20 shown in FIGURE 4, air discharging from the release chamber 22 past the cover 64 and out of the lateral ports 19 creates a low pressure area in the vicinity of the radial ports 67 due to Bernoullis effect. This maintains a vented condition in the control chamber 21. After the pressure in the release chamber 22 has been reduced to a relatively low pressure which is maintained by the continued application of high pressure air since the blowdown valve is not closed, the discharge valve 20 starts to close. A slight pressure builds up against the discharge valve 20 as the cover 64 enters the replaceable valve seat 25. When this pressure times the area of the discharge valve 20 exposed thereto equals the force exerted by the spring 32, no further closing movement of the discharge valve 20 takes place. Under this condition the convex annular surface 23 is spaced from the knife edge 24 and the control chamber 21 continues to be vented through the lateral ports 19 to the atmosphere. When the blowdown valve is close and air under pressure no longer is supplied to the release chamber 22, the spring 32 is able to move the discharge valve 20 to the fully closed position.

Now it will be apparent why the inwardly flared annular surface 28 is provided leading from the counterbore 27 in the replaceable valve seat 25. As the discharge valve 20 is moved toward the closed position, the cover 64 is guided by the inwardly flared annular surface 28 into the fully closed position. This prevents any peening or spalling of the annular knife edge 24 as the cover 64 moves toward the closed position.

As pointed out hereinbefore, the relation between the diameter of the cover 64 and the diameter of the cylindrical surface 29 is such as to provide the annular clearance opening 69 of the order of .003 to .006 inch. This clearance is such that the slow leakage from the release chamber 22 into the control chamber 21 is rapid enough to hold the discharge valve 20 closed so that it does not open during filling. However, this clearance opening is small enough that the opening of the control valve 49 bleeds the pressure in the control chamber 21 low enough to permit operation of the discharge valve 20 to the open position at the predetermined pressure.

Referring now particularly to FIGURES 6 and 7 of the drawings, it will be observed that a construction is shown which is similar to that illustrated in FIGURES 1, 2, 3 and 4 of the drawings. However, in the construction shown in FIGURES 6 and 7 a tubular discharge head body 74 can be employed which is somewhat shorter than the tubular head body 18 previously described. Within the tubular discharge head body 74 there is provided the cylindrical control chamber 21' and in it is slidably mounted a tubular cylindrical discharge valve 75 which is provided at its left end with a radially inwardly extending shoulder 76 against which one end 77 of a coil compression spring 78 reacts. In fully closed position the valve 75 closes off the lateral ports 19' in the head body 74. The other end 79 of the coil compression spring 78 is anchored against a valve seat member 80 which corresponds, generally, with the valve seat member 35 pre viously described. The valve seat member 80 is provided with a single discharge opening 81 which constitutes an extension of the opening through the hardened annular insert 55 which can be employed and is constructed in the manner hereinbefore described for cooperation with the control valve 49 that is slidably mounted in the cylindrical valve chamber 50 in the control valve body 39. Since the coil compression spring 78 is telescoped at its left end within the tubular cylindrical discharge valve 75, rather than being disposed to react against one end as is the case for the discharge valve 20, it is possible to reduce the length of the tubular discharge head body 74 and thus reduce the overall length of the automatic discharge head.

The tubular cylindrical discharge valve 75 is provided with an annular convex surface 82 for sealing engagement against the annular knife edge 24 of the replaceable valve seat which is constructed in the manner described hereinbefore. Inwardly of the annular convex surface 82 is a neck portion 83 through which radial ports 84 extend underneath a cover 85 which is formed integrally with the neck 83 that, in turn, is formed integrally with the tubular cylindrical valve 75. It will be observed that the release chamber 22 is placed in communication with the control chamber 21 through the annular clearance opening 69 between the cover 85 and the inner surface 29 of the valve seat 25, through the radial ports 84 and a central opening 86 at the left end of the discharge valve 75. The movement of the discharge valve 75 in the opening direction is limited by engagement of a shoulder 87 thereon with a shoulder 88 at the left end of the valve seat member 80.

The operation of the modification of the invention shown in FIGURES 6 and 7 of the drawings is essentially the same as that described for the construction shown'in FIGURES 1-4.

FIGURES 8 and 9 of the drawings show a tubular cylindrical discharge valve 91 that can be substituted for the discharge valve 75 shown in FIGURES 6 and 7 of the drawings. It will be observed that the discharge valve 91 is provided with an annular convex surface 92 for engagement with the annular knife edge 24 on the valve seat 25. The left end of the discharge valve 91 is closed by a cover 93 which is provided with an integrally formed annular flange 94 that has a press fit with the interior of the discharge valve 91. A shoulder 95 on the under side of the cover 93 limits the extent that the flange 94 can be telescoped within the discharge valve 91. Radial ports 96 extend through the annular flange 94 to provide a path for the gas charge to flow into the control chamber 21 during the charging operation and to permit the control chamber 21 to be discharged and eifect rapid opening of the discharge valve 91 when the control valve 49 operates in the manner described hereinbefore to vent the gintrol chamber 21 to the atmosphere through the vents FIGURE 10 of the drawings shows a discharge valve 99 that can also be used instead of the discharge valve 75 previously described and shown in FIGURES 6 and 7 of the drawings. The discharge valve 99 is provided with the annular convex surface 100 for engaging the annular knife edge 24 on the valve seat 25. The left end of the discharge valve 99 is closed by a cover 101 which is provided with an integral annular flange 102 that is threaded at 103 into the left end of the discharge valve 99. A shoulder 104 on the cover 101 limits the extent that the flange 102 can be threaded into the discharge valve 99. Radial ports 105 are provided in the annular flange 102 fs'or the purpose described hereinbe-fore for the radial ports FIGURES 11 and 12 show still another discharge valve 108 which can be employed in lieu of the discharge valve 75 shown in FIGURES 6 and 7 of the drawings. It is provided with an annular convex shoulder 109 for engaging the annular knife edge 24 of the valve seat 25. The left end of the discharge valve 108 is closed by a cover 110 which is provided with an annular flange 111 that interfits with a radially inwardly extending flange 112 formed integrally with the discharge valve 108. A shoulder 113 on the cover 110 limits the extent of inward movement of the annular flange 111 through the radially inwardly extending flange 112. Radial ports 114 are provided in the annular flange 111 and they function in the manner described hereinbefore for the ports 84. In order to hold the cover 110 in place, a bolt 115 extends therethrough and also through a spider 116 which overlies the inner surface of the radially inwardly extending flange 112. Openings 117 are provided in the spider 116 to place the radial ports 114 in communication with the interior of the discharge valve 108 and thereby with the control chamber 21.

Since certain further changes can be made in the foregoing constructions and different embodiments of the invention can be made Without departing from the spirit and scope thereof, it is intended that all matter shown in the accompanying drawings and described hereinbefore shall be interpreted as illustrative and not in a limiting sense.

What is claimed as new is:

1. In combination; a cylindrical cartridge body having arranged successively longitudinally thereof in the order named a cylindrical release chamber in which a material breaking chargeof compressed gas is to be developed and from which the charge is to be released, lateral gas charge release ports, and a cylindrical control chamber; means providing an anular valve seat at the end of said release chamebr adjacent said release ports, a cylindrical tubular discharge valve slidable in said control chamber and overlying said release ports, means biasing one end of said discharge valve into sealing engagement with said valve seat, cover means closing off said one end of said discharge valve between said release chamber and the area of sealing contact engagement with said valve seat, the peripheral surface of said cover means being spaced radially inwardly from the juxtaposed surface of said means providing said valve seat thereby forming an'annular clearance space, there being at least one passageway through said discharge valve underneath said cover means placing said annular clearance space in communication with said control chamber to permit the flow of gas from said release chamber to said control chamber at a rate which will maintain the pressure in said control and release chambers substantially equal during development of said charge in said release chamber while said sealing engagement is maintained with said valve seat, and means for lowering the gas pressure in said control chamber to a value substantially below that of the gas in said release chamber thereby permitting the gas pressure in said release chamber to move said discharge valve away from said valve seat and to uncover said lateral gas charge release ports and the compressed gas to be discharged therethrough, said one passageway being so positioned in said discharge valve that movement thereof out of sealing engagement with said valve seat toward open position places said control chamber in communication with at least one of said lateral gas charge release ports whereby sufiicient pressure is prevented from building up in said control chamber to close said discharge valve and the same remains open once it has been opened as long as the force exerted by the compressed gas in said release chamber against said cover means is greater than the force exerted by said biasing means tending to close said discharge valve.

2. In combination; a cylindrical cartridge body having arranged successively longitudinally thereof in the order named a cylindrical release chamber in which a material breaking charge of compressed gas is to be developed and from which the charge is to be released, lateral gas charge release ports, and a cylindrical control chamber; means providing an annular valve seat at the end of said release chamber adjacent said release ports, a cylindrical tubular discharge valve slidable in said control chamber and overlying said release ports, means biasing one end of said discharge valve into sealing engagement with said valve seat, cover means closing off said one end of said discharge valve between said release chamber and the area of sealing contact engagement with said valve seat, the peripheral surface of said cover means being spaced radially inwardly from the juxtaposed surface of said means providing said valve seat thereby forming an annular clearance space, there being at least one passageway through said discharge valve underneath said cover means placing said annular clearance space in communication with said control chamber to permit the flow of gas from said release chamber to said control chamber at a rate which will maintain the pressure in said control and release chambers substantially equal during development of said charge in said release chamber while said sealing engagement is maintained with said valve seat, and a control valve and means normally biasing it closed, said control valve being responsive to increase in gas pressure in said control chamber to a predetermined value for venting it to the atmosphere to lower the gas pressure therein to a value substantially below that of the gas in said release chamber thereby permitting the gas pressure in said release chamber to move said discharge valve away from said valve seat and to uncover said lateral gas charge release ports and the compressed gas to be discharged therethrough, said one passageway being so positioned in said discharge valve that movement thereof out of sealing engagement with said valve seat toward open position places said control chamber in communication with at least one of said lateral gas charge release ports whereby after said control valve has been reclosed by its biasing means suflicient pressure is prevented from building up in said control chamber to close said discharge valve and the same remains open as long as the force exerted by the compressed gas in said release chamber against said cover means is greater than the force exerted by the first mentioned biasing means tending to close said discharge valve.

3. In combination; a cylindrical cartridge body having arranged successively longitudinally thereof in the order named, a cylindrical release chamber in which a material breaking charge of compressed gas is to be developed and from which the charge is to be released, lateral gas charge release ports, and a cylindrical control chamber; means providing an annular valve seat at the end of said release chamber adjacent said release ports, a cylindrical tubular discharge valve slidable in said control chamber and overlying said release ports, means biasing one end of said discharge valve into sealing engagement with said valve seat, cover means closing olf said one end of said discharge valve between said release chamber and the area of sealing contact engagement with said valve seat, the peripheral surface of said cover means being spaced radially inwardly from the juxtaposed surface of said means providing said valve seat thereby forming an annular clearance space, there being a plurality of radial passageways through said discharge valve underneath said cover means placing said annular clearance space in communication with said control chamber to permit the flow of gas from said release chamber to said control chamher at a rate which will maintain the pressure in said control and release chambers substantially equal during development of said charge in said release chamber while said sealing engagement is maintained with said valve seat, and means responsive to increase in gas pressure in said control chamber to a predetermined value for lowering the gas pressure therein to a value substantially below that of the gas in said release chamber thereby permitting the gas pressure in said release chamber to move said discharge valve away from said valve seat and to uncover said lateral gas charge release ports and the compressed gas to be discharged therethrough, said passageways being so positioned in said discharge valve that movement thereof out of sealing engagement with said valve seat toward open position places said control chamber in communication with said lateral gas charge release ports 9 whereby sufficient pressure is prevented from building up in said control chamber to close said discharge valve and the same remains open once it has been opened as long as compressed gas is supplied to said release chamber.

4. The invention, as set forth in claim 3, wherein the cover means is an integral part of the tubular discharge valve and the radial passageways are formed in a connecting portion between the cover means and the main portion of the tubular discharge valve.

5. In combination; a cylindrical cartridge body having arranged successively longitudinally thereofin the order named a cylindrical release chamber in which a material breaking charge of compressed gas is to be developed and from which the charge is to be released, lateral gas charge release ports, and a cylindrical control chamber; an an nular valve seat at the end of said release chamber adjacent said release ports having an annular knife edge, a cylindrical tubular discharge valve slidable in said control chamber and overlying said release ports and having a convex annular surface at one end, means biasing said discharge valve and said convex annular surface thereon into sealing engagement with said annular knife edge on said valve seat, a cover closing off said one end of said discharge valve between said release chamber and said convex annular surface on said valve seat, said annular valve seat being flared inwardly from said annular knife edge to guide said cover into operative position when said discharge valve is moved to closed position, the peripheral surface of said cover being spaced radially inwardly from the juxtaposed surface of said means providing said valve seat thereby forming an annular clearance space, there being at least one passageway through said discharge valve underneath said cover means placing said annular clearance space in communication with said control chamber to permit the flow of gas from said release chamber to said control chamber at a rate which will maintain the pressure in said control and release chambers substantially equal during development of said charge in said release chamber while said sealing engagement is maintained with said valve seat, and means responsive to increase in gas pressure in said control chamber to a predetermined value for lowering the gas pressure therein to a value substantially below that of the gas in said release chamber thereby permitting the gas pressure in said release chamber to move said discharge valve away from said valve seat and to uncover said lateral gas charge release ports and the compressed gas to be discharged therethrough, said one passageway being so positioned in said discharge valve that movement thereof out of sealing engagement with said valve seat toward open position places said control chamber in communication with at least one of said lateral gas charge release ports whereby sufficient pressure is prevented from building up in said control chamber to close said discharge valve and the same remains open once it has been opened as long as compressed gas is supplied to said release chamber.

6. In combination; a cylindrical cartridge body having arranged successively longitudinally thereof in the order named a cylindrical release chamber in which a material breaking charge of compressed gas is to be developed and from which the charge is to be released, lateral gas charge release ports, and a cylindrical control chamber; means providing an annular valve seat at the end of said release chamber adjacent said release ports, a cylindrical tubular discharge valve slidable in said control chamber and overlying said release ports, said discharge valve having sealing engagement at one end with said valve seat and being open at the other end, a cover closing ofl? said one end of said discharge valve between said release chamber and the area of sealing contact engagement with said valve seat, the peripheral surface of said cover being spaced radially inwardly from the juxtaposed surface of said means providing said valve seat thereby forming an annular clearance space, there being at least one passageway through said discharge valve underneath said cover placing said annular clearance space in communication with said control chamber to permit the flow of gas from said release chamber to said control chamber at a rate which will maintain the pressure in said control and release chambers substantially equal during development of said charge in said release chamber while said sealing engagement is maintained with said valve seat, a coil compression spring in said control chamber anchored at one end therein and telescoped at its other end Within said tubular discharge valve and biasing it into closed position, and means responsive to increase in gas pressure in said control chamber to a predetermined value for lowering the gas pressure therein to a value substantially below that of the gas in said release chamber thereby permitting the gas pressure in said release chamber to move said discharge valve away from said valve seat and to uncover said lateral gas charge release ports and the compressed gas to be discharged therethrough, said one passageway being so positioned in said discharge valve that movement thereof out of sealing engagement with said valve seat toward open position places said control chamber in communication with at least one of said lateral gas charge release ports whereby suflicient pressure is prevented from building up in said control chamber to close said discharge valve and the same remains open once it has been opened as long as compressed gas is supplied to said release chamber.

7. In combination; a cylindrical cartridge body having arranged successively longitudinally thereof in the order named a cylindrical release chamber in which a material breaking charge of compressed gas is to be developed and from which the charge is to be released, lateral gas charge release ports, a cylindrical control chamber, and a valve chamber having a vent to the atmosphere; means providing an annular valve seat at the end of said valve slidable in said control chamber at one end thereof and overlying said release ports, said discharge valve having sealing engagement at one end with said valve seat at the end of said release chamber adjacent said release ports, a cylindrical tubular discharge valve slidable in said control chamber at one end thereof and overlying said release ports, said discharge valve having sealing engagement at one end with said valve seat and being open at the other end, a cover closing off said one end of said discharge valve between said release chamber and the area of sealing contact engagement with said valve seat, the peripheral surface of said cover being spaced radially inwardly from the juxtaposed surface of said means providing said valve seat thereby forming an annular clearance space, a control valve seat member forming a closure for the other end of said control chamber and having a discharge opening therethrough, a control valve closing said discharge opening and slidable in said valve chamber and responsive to increase in gas pressure in said control chamber to a predetermined value for placing said discharge opening in communication with said vent to reduce the control chamber pressure to a value substantially below that of the gas in said release chamber thereby permitting the gas pressure in said release chamber to move said discharge valve into said control chamber away from said annular valve seat and place said lateral gas charge release ports in direct communication with said release chamber, means biasing said control valve to closed position, a coil compression spring in said control chamber at one end reacting against said valve seat member and telescoped at its other end within said tubular discharge valve and biasing it toward closed position, and radial port means in said discharge valve beneath said cover placing said release chamber in communication with said control chamber through said clearance space and said tubular discharge valve when it engages said annular valve seat to permit the flow of gas from said release chamber to said control chamber at a rate Which will maintain the pressure in said control and release chambers substantially equal during development of said charge in said release chamber, said radial port means being so positioned in said discharge valve that movement thereof out of sealing engagement with said valve seat toward open position places said control chamber in communication therethrough with said lateral gas charge release ports whereby after said control valve has been reclosed sufiicient pressure is prevented from building up in said control chamber to close said discharge valve and the same remains open as long as the force exerted by the compressed gas in said release chamber against said cover is greater than the force exerted by said coil compression spring tending to close said discharge valve.

8. In combination; a cylindrical cartridge body having arranged successively longitudinally thereof in the order named a cylindrical release chamber in which a material breaking charge of compressed gas is to be developed and from which the charge is to be released, lateral gas charge release ports, and a cylindrical control chamber; means providing an annular valve seat at the end of said release chamber adjacent said release ports, a cylindrical tubular discharge valve slidable in said control chamber and overlying said release ports, means biasing one end of said discharge valve into sealing engagement with said valve seat, a cover having an integral annular flange telescoped with said one end of said discharge valve, the peripheral surface of said cover being spaced radially inwardly from the juxtaposed surface of said means providing said valve seat thereby forming an annular clearance space, there being at least one radial passageway through said annular flange underneath said cover placing said annular clearance space in communication with said control chamber to permit the flow of gas from said release chamber to said control chamber at a rate which will maintain the pressure in said control and release chambers substantially equal during development of said charge in said release chamber while said sealing engagement is maintained with said valve seat, and means responsive to increase in gas pressure in said control chamber to a predetermined value for lowering the gas pressure therein to a value substantially below that of the gas in said'release chamber thereby permitting the gas pressure in said release chamber to move said discharge valve away from said valve seat and to uncover said lateral gas charge release ports and the compressed gas to be discharged therethrough, said one passageway being so positioned in said discharge valve that movement thereof out of sealing engagement with said valve seat toward open position places said control chamber in communication with at least one of said lateral gas charge release ports whereby suflicient pressure is prevented from building up in said control chamber to close said discharge valve and the same remains open once it has been opened as long as compressed gas is supplied to said release chamber.

References Cited in the file of this patent UNITED STATES PATENTS 788,867 VVehner May 2, 1905 2,532,578 Spencer Dec. 5, 1950 2,583,295 Greer Jan. 22, 1952 2,703,705 Boller Mar. 8, 1955 2,720,169 Smith Oct. 11, 1955 

